(ii) Non-random Mating Repeated mating between individuals of certain selected traits changes the gene frequency, e.g., selection of more brightly coloured male bird by a female bird may increase the gene frequency of bright colour in the next generation.
(iii) Gene Flow (Gene Migration) It is the movement of alleles into and out of a gene pool.
- Breeding of immigrants with the host population adds new alleles to the gene pool of the host population.